introduction: the purpose of this study was to evaluate the effect of different solvents; carbonic acid (h 2 co 3 ), hydrochloric acid (hcl), chlorhexidine (chx) and sodium hypochlorite (naocl) on the surface hardness of mineral trioxide aggregate (mta) and calcium-enriched mixture (cem) cement. methods and materials: plexiglass molds were prepared and filled with angelus mta or cem cement and ...

nitration of phenol and various 4-substituted phenols with cu(no3)2.3h2o, cu(no3)2.3h2o/sio2, 9h2o and cr(no3)2. 9h2o in different anhydrous organic solvents are investigated. high selectivity ratio of para vs ortho isomers has been observed. mono- and dinitro compounds from phenol and 4-substituted phenols by choosing the proper solvents and reaction conditions, are also obtained with high sel...